The present invention refers to an electronic length measuring device, especially intended for measuring and summation of lengths of wood- or steel goods, comprising a measuring tape which is rolled up in a gauging station.
At retail sale of for example wood-products the lengths of the wood-products are measured with the assistance of conventional folding rules, measuring-tapes or some kind of measuring-planks. The lengths of the wood-products are thereafter summed up by hand or with the assistance of a mechanical or an electronical calculator. This procedure is of course time-wasting and there is a great risk of getting incorrect readings and incorrect summations.
In recent years more automatically working length measuring devices have been development. Such a length measuring device is described in for example the DE-OS No. 2.826.030. This publication shows a measuring equipment in which an extensible measuring-tape is included and with such an equipment different lengths can be measured. The measuring-tape is provided with perforations which engage a gear wheel. The gear wheel is arranged at the end of an axle on the opposite end of which a rotary disk is mounted. The disk is provided with a number of holes arranged in a circle near the periphery of the disk. A detecting-device is arranged to detect the number of holes that passes through the detecting-device.
The thus demonstrated testing-device is suffering from several disadvantages. One disadvantage is that when measuring wood-products, as planks and other long articles, the operator first manually has to unwind the measuring-tape to the full length of the measuring object, thereafter go back to the measuring equipment and initiate a measuring instruction to the electronics by pushing a switch. This procedure must than be repeated for every measuring object. This results in a slow measuring procedure and compared to a conventional measuring system no time saving to speak of is obtained. Furthermore no automatic summation is obtained in a case when a number of measuring objects are to be measured and summed up, which often is the case when wood-articles and the like is measured. An additional disadvantage is the problem of at which direction the tape is running at the different measuring occasions. This has not either been satisfactory solved, which means that incorrect readings can occur if the operator, when measuring the length, allows the tape to move in and out at the same measurement occasion.